1. Field of the Invention
This invention relates to the production of shale oil and more particularly to the in-situ retorting of oil shale to produce shale oil and the delivery of products from the retort to the surface.
2. Description of the Prior Art
A process that has been developed for the production of shale oil from oil shale is known as the in-situ retorting process. In that process, a retort filled with rubblized oil shale is constructed in the underground oil shale formation. The rubblized shale is heated to a temperature above about 88.degree. F. to produce shale oil from kerogen, a carbonaceous constituent in oil shale. In a preferred process for in-situ retorting, rubblized shale at the top of the in-situ retort is ignited by the burning of a fuel gas at the upper end of the retort and thereafter delivery of the fuel gas is terminated while injection of an oxygen-containing gas, usually air, into the upper end of the formation is continued to continue burning of carbonaceous material in the shale. Hot products of combustion pass downwardly through the shale to heat shale below the combustion front to a temperature at which kerogen is converted to shale oil. The gaseous products of combustion, the shale oil, and water resulting from the combustion or from leakage into the retort from aquifers are discharged from the bottom of the retort and delivered to the surface. Typical in-situ combustion processes for the production of shale oil are described in U.S. Pat. No. 1,919,636 of Karrick, U.S. Pat. No. 2,481,051 of Uren and U.S. Pat. No. 3,001,776 of Van Poollen.
The products discharged from the lower end of the retort are a mixture of carbon dioxide, air, carbon monoxide, water and some partially oxidized organic compounds. The complex mixture promotes the formation of an emulsion of the shale oil and water that is difficult to break. In U.S. Pat. No. 4,014,575 of French et al., a process is described for handling the products from an in-situ combustion retort in which liquids discharged from the retort are separated from the gaseous products and pumped from an underground sump to a separator at the surface. The intense mixing of the shale oil with aqueous liquids in the pump and the pipeline to the surface can aggravate the formation of emulsions.